In recent years, improvement of a working environment for an operator has been strongly desired in view of both health and efficiency. For example, a large scale crane or the like installed in a factory generates large vibration to vibrate a floor surface of a building in the vicinity thereof, resulting in a harmful effect on the working environment for the operator. Further, equipments in a production factory have been progressively computerized, and the working environment has changed to an intelligent working area into which, for example, many precision apparatuses are introduced. Therefore, improvement for working has been increasingly important.
As a method of carrying out the improvement for working, it can be considered that a floor member of the building may be supported by a laminated rubber in which a plurality of steel plates and rubber plates are laminated. However, the laminated rubber is soft in a horizontal direction, but is hard in a vertical direction. Thus, only small effect can be expected in reduction of the vibration in the factory due to the crane or the like.
Further, though it can be considered that the floor member of the building may be supported by a coil spring which can withstand relatively large load, the following problems are caused.
In order to provide the coil spring withstanding the large load, it is sufficient to simply provide a thick and large spring material. However, in the manufacture of the large-scale coil spring, a larger equipment and more complicated procedure are required than those required for a small coil spring, resulting in problems of considerably increased cost, a more increased height and so forth. In addition, since the coil spring itself has a small vibration damping effect, the generating vibration can not be easily stopped. Hence, a shock absorber is also mounted. However, complicated mounting operation is necessary to rigidly secure the shock absorber to both a base and a supported body. Alternatively, there is another method of immersing the coil spring in damping liquid to promote a damping effect (see, for example, Japanese Utility Model Laid-open No. 3-32229). However, it is impossible to efficiently damp by simply immersing the coil spring in the damping liquid.
A description will now be given of a steel damper, and a viscous damper serving as a typical shock absorber. Though the steel damper is relatively inexpensive, the steel damper can not damp in small deformation (in yield deformation or earlier deformation), and can provide only small vibration isolating effect with respect to small or middle scale vibration. The viscous damper can provide some vibration isolating effect with respect to the small or middle scale vibration. However, the viscous damper requires maintenance due to a lifetime of viscosity, and is expensive.
Alternatively, a composite body including a gelled material and the coil spring is disclosed in, for example, Japanese Patent Laid-open No. 1-182644. The composite body can serve as the composite body including the gelled material and the coil spring in a vertical direction, but can not serve with respect to vibration in horizontal and rotary directions. Consequently, there is a drawback in that the vibration isolating effect can not be expected.
In view of the facts set forth above, it is an object of the present invention to provide a vibration isolating supporter which can withstand the large load, and can efficiently perform a vibration isolating action.